During backup of a database's data stored in individual files, it is not permissible for the data in the individual files to be altered, for reasons of consistency. For this reason, the files are blocked to altering access operations after a particular time during a backup operation. When the files have been copied, the block is lifted again.
As the size of the database increases, the time required for such a backup operation increases. This results in the performance and operability of the system accessing the individual files of the database being impaired during a backup operation.
To avoid this problem, it is possible to use a method which, although permitting the alterations, does not incorporate them into the files of the database to be backed up during the backup operation. Rather, it creates a separate recording file which would be incorporated into the database's files when the backup operation has ended. During processing of the first recording file, it would have to be assumed that there are alterations to the files of the database. For reasons of consistency, these alterations would not be able to be made until after all the alterations from the first recording file had been incorporated, and would therefore need to be captured in a second recording file. The method would become unstable if the second recording file were to grow faster than the first recording file could be processed.
One problem in connection with data backup is that of shortening the duration of the block required for the entire database while the files are being copied such that instabilities do not arise, without restricting the scope of the backup operation in doing so.